You need to add a data template with a textbox in it as shown below :
<TreeView x:Name="MyTreeView">
<TreeView.Resources>
<DataTemplate x:Key="NormalTemplate">
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding ID}" Margin="3"/>
<TextBlock Text="-" Margin="3"/>
<TextBlock Text="{Binding Name}" Margin="3"/>
</StackPanel>
</DataTemplate>
<DataTemplate x:Key="EditTemplate">
<TextBox Text="{Binding Name}"/>
</DataTemplate>
</TreeView.Resources>
<TreeView.ItemTemplate>
<HierarchicalDataTemplate
ItemsSource="{Binding Team}">
<ContentPresenter Content="{Binding}">
<ContentPresenter.Style>
<Style TargetType="{x:Type ContentPresenter}">
<Setter Property="ContentTemplate"
Value="{StaticResource
NormalTemplate}"/>
<Style.Triggers>
<DataTrigger
Binding="{Binding IsSelected,
RelativeSource={RelativeSource
FindAncestor,
AncestorType={x:Type TreeViewItem}}}"
Value="True">
<Setter Property="ContentTemplate"
Value="{StaticResource
EditTemplate}" />
</DataTrigger>
</Style.Triggers>
</Style>
</ContentPresenter.Style>
</ContentPresenter>
</HierarchicalDataTemplate>
</TreeView.ItemTemplate>
</TreeView>
Do let me know it this helped !!!
Full source :
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